Oil prices climbed more than $1 on Monday, regaining some of last week's losses, after OPEC+'s output hike was seen as modest and due to concerns over the possibility of more sanctions on Russian crude.

OPEC+ flagged plans to further increase production from October, but the amount was less than some analysts had anticipated. Reuters reported earlier this month that members were considering another hike.

"The market had run ahead of itself regarding this OPEC+ increase," said Ole Hansen, head of commodity strategy at Saxo Bank. "Today we're seeing a classic sell the rumour, buy the fact reaction."

Brent crude climbed $1.28, or 1.95%, to $66.78 a barrel by 1031 GMT, while US West Texas Intermediate crude rose $1.20, or 1.94%, to $63.07 a barrel.

Both benchmarks fell more than 2% on Friday as a weak US jobs report dimmed the outlook for energy demand. They lost more than 3% last week.

OPEC+, which includes the Organization of the Petroleum Exporting Countries plus Russia and other allies, agreed on Sunday to further raise oil production from October.

OPEC+ has been increasing production since April after years of cuts aimed at supporting the oil market. The latest decision comes despite a likely looming oil glut in the Northern Hemisphere winter months.

The eight members of OPEC+ will lift production from October by 137,000 barrels per day. That, however, is much lower than increases of about 555,000 bpd for September and August and 411,000 bpd in July and June.

The impact of the latest increase is expected to be relatively low because some members have been overproducing. So the higher output level would likely include barrels that are already in the market, analysts said.

"Expectations of tighter supply from potential new U.S. sanctions on Russia are also lending support," said Toshitaka Tazawa, an analyst at Fujitomi Securities.

US President Donald Trump said on Sunday he is ready to move to a second phase of sanctioning Russia, the closest he has come to suggesting he is on the verge of ramping up sanctions against Moscow or its oil buyers over the war in Ukraine

New sanctions on buyers of Russian oil could disrupt crude flows, energy trader Gunvor's global head of research and analysis, Frederic Lasserre, said on Monday.

Russia launched its largest air attack of the Ukraine war over the weekend, setting the main government building on fire in central Kyiv and killing at least four people, Ukrainian officials said.

Trump said on Sunday that individual European leaders would visit the United States on Monday and Tuesday to discuss how to resolve the conflict.

In a note over the weekend, Goldman Sachs said it expects a slightly larger oil surplus in 2026 as supply upgrades in the Americas outweigh a downgrade to Russia supply and stronger global demand. It left its Brent/WTI price forecast unchanged for 2025 and projected the 2026 average at $56/$52 a barrel.